Tech Mahindra Team Lead Interview Questions, Process, and Tips

To find 3rd column in a pipe delimited file in unix, use the cut command.

• Use the cut command with -d option to specify the delimiter as pipe(|)

• Use -f option to specify the field/column number to extract, in this case 3

• Example: cut -d '|' -f 3 filename.txt

• This will output the 3rd column from the file filename.txt

I have used various libraries in Python such as NumPy, Pandas, Matplotlib, Scikit-learn, etc.

• NumPy - for numerical computations and array manipulation

• Pandas - for data manipulation and analysis

• Matplotlib - for data visualization

• Scikit-learn - for machine learning tasks

• Requests - for making HTTP requests

• BeautifulSoup - for web scraping

• NLTK - for natural language processing

• OpenCV - for computer vision tasks

Dense rank assigns consecutive integers to distinct values, rank assigns integers to distinct values but skips integers for ties, row number assigns integers to rows in the result set.

• Dense rank assigns consecutive integers to distinct values

• Rank assigns integers to distinct values but skips integers for ties

• Row number assigns integers to rows in the result set

• Dense rank and rank are used for ranking data, while row nu...read more

Hive supports various analytical functions for data processing and analysis.

• Hive supports aggregation functions like SUM, COUNT, AVG, MIN, MAX, etc.

• It also supports window functions like ROW_NUMBER, RANK, LAG, LEAD, etc.

• Hive provides statistical functions such as CORR, COVAR_POP, STDDEV, etc.

• It supports date and time functions like YEAR, MONTH, DAY, HOUR, etc.

• Hive also offers string manipulation functions like CONCAT,

Multi array transformation in JSON in Kafka

• Use a JSON serializer and deserializer to convert multi arrays to JSON and vice versa

• Ensure that the data is properly formatted and validated before sending it to Kafka

• Consider using a schema registry to manage the schema for the JSON data

• Test the transformation thoroughly to ensure that it is working as expected

Lambda function is a small anonymous function in Python.

• Lambda functions can have any number of arguments but only one expression.

• They are used as a shortcut to define small functions without a name.

• Lambda functions can be used as arguments to higher-order functions.

• Example: lambda x: x**2 defines a function that squares its input.

• Example: sorted(list, key=lambda x: x[1]) sorts a list of tuples by the second element.

Null values in HIVE can be eliminated using the COALESCE function.

• Use the COALESCE function to replace null values with a default value.

• Syntax: COALESCE(column_name, default_value)

• Example: SELECT COALESCE(name, 'Unknown') FROM table_name;

ACID properties ensure data consistency and reliability in HIVE tables.

• ACID stands for Atomicity, Consistency, Isolation, and Durability.

• Atomicity ensures that a transaction is treated as a single unit of work.

• Consistency ensures that the data remains in a valid state before and after the transaction.

• Isolation ensures that concurrent transactions do not interfere with each other.

• Durability ensures that once a transacti...read more

To get the 3rd highest salary in an employee table, we can use the SQL query with the 'LIMIT' and 'OFFSET' clauses.

• Write a SQL query to select the distinct salaries from the employee table in descending order.

• Use the 'LIMIT' clause to limit the result to the third row.

• Use the 'OFFSET' clause to skip the first two rows.

• The result will be the 3rd highest salary in the employee table.